Shear Resistant Wound Dressing for Use in Vacuum Wound Therapy

ABSTRACT

A cover layer for a vacuum wound therapy dressing includes a backing layer formed from a flexible polymeric membrane and an adhesive layer for affixing the backing layer over a wound bed to provide a substantially fluid-tight seal around a perimeter of the wound bed. The cover layer is reinforced with a reinforcement layer extending to a peripheral region of the backing layer to distribute forces associated with evacuating a reservoir, as defined by or within the cover, to stimulate healing of the wound bed.

CROSS REFERENCE TO RELATED APPLICATION

This application claims priority to, and the benefit of, U.S.Provisional Application Ser. No. 61/036,275, filed on Mar. 13, 2008 byVitaris, the entire contents of which are being hereby incorporated byreference herein.

BACKGROUND

1. Technical Field

The present disclosure relates generally to a wound dressing fortreating an open wound with a vacuum wound therapy procedure. Inparticular, the disclosure relates to a wound dressing employing areticulated or net-like reinforcement structure to protect the woundthroughout the procedure.

2. Background of Related Art

The body's natural wound healing process is a complex series of eventsbeginning at the moment of injury. Initially the body reacts bydelivering proteins and other factors to the wound through the bloodstream to minimize the damage. Blood clots to prevent blood loss whilecells engulf bacteria and debris to carry it away from the wound site.Next, the body begins to repair itself in a stage of healing oftenreferred to as the proliferate phase. This phase is characterized by thedeposition granulation tissue in the wound bed. Granulation tissueprovides a base structure over which cells may migrate inwardly from theperiphery to close the wound. Finally the process ends as collagen givesstrength to new tissue over time often forming a scar.

One technique for promoting the natural healing process, particularly,but not exclusively during the proliferate phase, is known as vacuumwound therapy (VWT). Application of a reduced pressure, e.g.sub-atmospheric, to a localized reservoir over a wound has been found toassist in closing the wound. The reduced pressure may be effective topromote blood flow to the area, to stimulate the formation ofgranulation tissue and the migration of healthy tissue over the wound bythe natural process. Also a reduced pressure may assist in removingfluids exuding from the wound, which may inhibit bacterial growth. Thistechnique has proven effective for chronic or non-healing wounds, buthas also been used in for other purposes such as post-operative woundcare.

The general VWT protocol provides for the introduction of a fillermaterial into the wound to absorb exudates and promote fluid transportaway from the wound bed. The wound filler may comprise such materials asnon-reticulated foams, non-woven reinforcements or gauze. The wound andthe absorbent wound filler material may then be covered by a flexiblecover layer having an adhesive periphery that forms a substantiallyfluid tight seal with the healthy skin surrounding the wound. The coverlayer thus defines a vacuum reservoir over the wound where a reducedpressure may be maintained over time by individual or cyclic evacuationprocedures.

An aspect of concern in a VWT treatment is the management of forcesgenerated in the dressing when a reduced pressure is applied. Theseforces may undesirably deform a flexible cover layer, draw theperi-wound margins into the wound and put the surrounding skin intension. These same forces may significantly compress the absorbentfiller such that it forms a rigid mass. In such a state, the filleradopts an increased tendency to adhere to the wound bed, restricts thefluid passages available for exudate transport and inhibits penetrationof the reduced pressure there through. Accordingly, a need exists for adressing suitable for use in a VWT procedure.

SUMMARY

The present disclosure describes a dressing for use in a vacuum woundtherapy procedure to promote healing of a wound. The dressing includes acover layer having an integrated support structure to manage forcesassociated with a VWT procedure. The cover layer includes a backinglayer formed from a flexible polymeric membrane, an adhesive layer toaffix the backing layer over a wound and provide to a seal around thewound bed, and a reticulated or net-like reinforcement layer affixed tothe backing layer and extending to a peripheral region of the coverlayer. The net-like reinforcement layer stiffens the cover layer andcontributes to the ability of the cover layer to resist the deformationin the wound area commonly associated with a VWT procedure. Thus, thewound filler may be compressed to a minor degree such that it continuesto provide exudate transport and vacuum penetration. The use of thenet-like reinforcement layer may also lessen the degree to which thewound margin collapses, and may contribute to the manifestation offorces generated by the application of a reduced pressure as compressionforces rather than shear forces. Compression forces applied to a woundis well known to be a beneficial wound treatment.

The reinforcement layer may be formed from such structures as a mesh ofpolyethylene terephthalatae fibers, apertured films and thermoplasticnetting. The adhesive layer may be affixed to a peripheral region of thebacking layer and may include an opening such that the adhesive layerdoes not extend to a central region of the cover layer. The adhesivelayer may overlap a portion of the reinforcement layer such that thereinforcement layer is firmly affixed to the backing layer.Alternatively, the reinforcement layer may contain an appropriateadhesive coating to more firmly attach it to the backing layer. Thebacking layer may be formed from a polyurethane film having a thicknessfrom about 0.8 mils to about 1.0 mils, and may include an aperturetherein for facilitating connection of a vacuum port to the cover layer.The vacuum port may incorporate a filter screen defining a plurality ofopenings. The backing layer may be formed from a moisture vaporpermeable membrane.

According to another aspect of the disclosure a wound dressing systemincludes a contact layer and an absorbent filler positioned in a woundbed and covered by a cover layer. A vacuum reservoir is defined betweenthe cover layer and the wound bed. The cover layer includes a backinglayer formed from a flexible polymeric membrane, an adhesive layer toaffix the backing layer over a wound and provide to a seal around thewound bed, and a reinforcement layer affixed to the backing layer andextending to a peripheral region of the cover layer. A vacuum system isin fluid communication with the vacuum reservoir.

The contact layer may be formed from a conical apertured film to promoteunidirectional flow of exudates from the wound. The absorbent fillermaterial may include a single strand of a polyolefin filament. Also, thevacuum system may include a vacuum source, a collection canister and aone-way valve.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are incorporated in and constitute apart of this specification, illustrate embodiments of the presentdisclosure and, together with the detailed description of theembodiments given below, serve to explain the principles of thedisclosure.

FIG. 1 is an exploded perspective view of a vacuum wound therapy systemin accordance with the present disclosure;

FIG. 2 is an orthographic view of a wound facing side of the cover layerof FIG. 1;

FIG. 3 is an exploded cross sectional view taken along the line 3-3 ofFIG. 2;

FIG. 4A is a cross sectional view of the vacuum wound therapy system ofFIG. 1 installed over wound on a patient prior to application of areduced pressure;

FIG. 4B is a cross sectional view of the vacuum wound therapy system ofFIG. 1 installed over wound on a patient following an application of areduced pressure;

FIG. 5 is a top plan view of a vacuum port of FIG. 1;

FIG. 6 is a perspective view of the vacuum port of FIG. 5;

FIG. 7 is a perspective view of an alternative embodiment of a vacuumport;

FIG. 8 is an exploded perspective view of an alternative embodiment of avacuum port assembly including a portal member and an independent filterscreen;

FIG. 8A is a perspective view of the filter screen of FIG. 8 in analternate orientation;

FIG. 8B is a perspective view of an alternate embodiment of anindependent filter screen;

FIG. 9 is a bottom plan view of the portal member of FIG. 8;

FIG. 10 is a partial cross sectional view of the vacuum port assemblyassembled in a wound dressing; and

FIG. 11 is an exploded perspective view of an alternative embodiment ofa vacuum port assembly including a treatment element.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

The wound dressing of the present disclosure promotes healing of a woundby providing a reservoir over the wound where a reduced pressure may bemaintained. The reservoir subjects the wound to a sub-atmosphericpressure to effectively draw wound fluid, including liquid exudates,from the wound without the continuous use of a vacuum pump. Hence,vacuum pressure may be applied once, or in varying intervals dependingon the nature and severity of the wound. To facilitate fluid transportfrom the wound, a filler material may be included within the reservoirto promote the wicking of wound fluids subject to a reduced pressure.The use of a wound dressing in this manner has been found to promotehealing by reducing the probability of infection, stimulating thedeposition of granulation tissue and other beneficial processes. Thewound dressing of the present disclosure includes a cover layer having areinforcement structure to enhance the effect of a vacuum wound therapytreatment.

The attached figures illustrate exemplary embodiments of the presentdisclosure and are referenced to describe the embodiments depictedtherein. Hereinafter, the disclosure will be described in detail byexplaining the figures wherein like reference numerals represent likeparts throughout the several views.

Referring initially to FIG. 1, a vacuum wound therapy system accordingto the present disclosure is depicted generally as 10 for use on a wound“w” surrounded by healthy skin “s.” The vacuum wound therapy system 10includes a vacuum system 12 in fluid communication with a vacuumreservoir 14 (FIG. 4A) defined by or within wound dressing 16. Thevacuum system 12 includes a vacuum source 18 coupled to the dressing 16through a one-way valve 20 and a vacuum tube 24. A collection canister28 may be provided for wound drainage and debris. The vacuum system 12is adapted to provide a reduced pressure to the vacuum reservoir 14appropriate to stimulate healing of the wound “w.” A more detaileddescription of an appropriate vacuum system 12 is found in commonlyassigned U.S. Patent Application Publication 2007/0066946, the entirecontents of which are incorporated herein by reference.

A vacuum port 30, depicted in greater detail in FIG. 5 and FIG. 6, mayalso be included to facilitate connection of the vacuum system 12 to thedressing 16. The vacuum port 30 may be configured as a rigid orsemi-rigid, low-profile component adapted to receive the vacuum tube 24in a releasable and fluid-tight manner. The vacuum port 30 may beconfigured to include a wide and flexible flange 32 about its perimeter.The flange 32 permits an adhesive to be attached to either an undersideof flange 32 for securement to an outer surface of cover layer 44, or toa top side of flange 32 to provide for mounting to the underside of thereinforcement layer 46. Either configuration provides a mechanism forconnecting to the dressing 16. A hollow interior of the vacuum port 30provides fluid communication between the vacuum tube 24 and thereservoir 14 defined by or within dressing 16. A connector segment 33extends above the flange 32 for facilitating connection with the vacuumtube 24. It is envisioned that because of the possible intimateproximity of the vacuum port 30 to either reservoir 14 or wound filler38, the performance of vacuum port 30 may be enhanced by theincorporation of a filter screen 58 as depicted in FIG. 6 and FIG. 7.Filter screen 58 may inhibit the migration of large particles that mayotherwise be drawn into the vacuum port 30 and consequently create arestriction or blockage of the vacuum tube 24. The filter screen 58 maybe integral to the configuration of the vacuum port 30 as part of theport flange 32. The filter screen 58 may include a number of openings,each smaller than a cross-sectional area of the vacuum tube 24 or theopening in the vacuum port 30 adapted to receive the vacuum tube 24, andcollectively greater than the cross-sectional area of vacuum tube 24 orthe opening in the vacuum port 30 adapted to receive the vacuum tube 24.For example, the filter screen 58 of vacuum port 30 may include fourrelatively large openings, while the filter screen 58A of vacuum port30A depicted in FIG. 7 may include six relatively small openings. Theopenings in the filter screens 58, 58A are dimensioned to minimize thepassage of tissue particles of a predetermined dimension through therespective vacuum port 30, 30A.

Another alternate embodiment of a vacuum port is depicted generally as30B in FIGS. 8, 9, 10 and 11. Vacuum port 30B may be configured toaccept a filter screen 59 or 60 as a distinct or independentlymanufactured component as depicted in FIGS. 8, 10 and 11. An opening orcavity 31 depicted in the plan view of FIG. 9 and shown in phantom inFIG. 8 on an underside of vacuum port 30B may be adapted to permitfilter screen 59 to be permanently bonded therein such that filterscreen 59 is substantially flush with the underside of vacuum port 30B.Alternatively, filter screen 60 may be bonded to the opening on theunderside of vacuum port 30B. Filter screen may 60 includes a generallyflat base 62 through which the openings 65 extend, and a pair lips 64projecting from the base 62 along opposite edges of the filter screen60. The lips 64 may be dimensioned to be flush with a patient facingunder surface of the flange when received within the cavity 31.Alternatively the lips 64 may extend beyond the under surface of theflange to extend beyond the cavity 31 in the portal member 30B asdepicted in FIG. 10. Filter screen 60 may exhibit an increased surfacearea available for bonding within cavity 31 of vacuum port 30B. Filterscreen 60 may be secured within cavity 31 by bonding, cements, adhesivesor the like. In one embodiment, filter screen 62 is positioned withincavity 31 with lips 64 facing toward the wound (FIGS. 8 and 10). Inanother embodiment, filter screen 62 is positioned within lips 64 facingtoward vacuum port 30B and away from the wound (FIG. 8A). In anotherembodiment, base 62 is devoid of lips 64 as shown in FIG. 8B, and issubstantially planar.

It is also envisioned that filter screens 59 and 60 may be provided incombination with a treatment element 61 comprising a therapeuticmaterial as depicted in FIG. 11. Treatment element 61 may be insertedbetween filter screens 59, 60 and may secured to vacuum port 30B by anappropriate adhesive bond. The treatment element 61 and filter screens59, 60 may define an insert for reception into cavity or opening 31 onthe underside of portal member 30B. This arrangement may provide aconvenient method of treating the wound exudate as it is drawn from thewound “w.” Treatment element 61 may comprise fibrous or granulatedmaterials contained in a porous container or wrap to facilitateplacement between filter screens 59 and 60. Treatment element 61 mayinclude materials such as activated charcoal or other odor control orneutralizing substances. Treatment element 61 may includeanti-bacterials such as polyhexamethylene biguanide (PHMB). Also,antimicrobials such as ionic metals or biguinides may be included toreduce the bio-burden of the exudate or microbials within the exudate asthe exudate is drawn in to a collection canister 28. In the alternative,filter screens 59, 60 may comprise charcoal, antimicrobials, anti-odorsubstances.

Vacuum tube 30 may be configured to accept a variety of tubinggeometries such as round, oblong or elliptical. Vacuum port 30 may beprovided as a pre-affixed component of dressing 16, as part of vacuumsystem 12 or entirely independently. Also vacuum port 30 may not benecessary depending on the configuration of dressing 16.

Wound dressing 16 generally includes a contact layer 34, filler 38 and areinforced cover layer 40. Reinforced cover layer 40 may be formed froma composite including a backing layer 44, a reinforcement layer 46 andan adhesive layer 48. Each layer of wound dressing 16 is described ingreater detail below.

Contact layer 34 may be sufficiently conformable to be positioned indirect contact with an irregularly shaped surface of a wound bed “w.” Athin film of polyethylene or other suitable non-adherent material mayform the contact layer 34 to limit the adherence of filler 38 and othersubstances to the wound “w.” Apertures or perforations in the filmpermit fluids to pass through the contact layer 34, allowing for thesub-atmospheric pressure to penetrate into the wound “w” and forexudates to flow freely out of the wound “w.” By selecting anappropriate film material, the passage of wound exudate through contactlayer 34 may be controlled so as to be substantially unidirectional toprevent wound exudate from flowing back into the wound. To promote aunidirectional flow, a conical apertured film, such as those provided byTredegar Film Products of Richmond, Va., may be selected for formingcontact layer 34. This type of film is arranged with aperturespositioned at the peaks of cone shaped formations in the film materialsuch that exudate encounters the film as an array of micro-funnels inone direction and an array of collecting basins in the other. Though itis depicted in a square configuration, the shape of the contact layer 34can be customized to better suit the wound geometry. Unidirectional flowof exudates may also be promoted by the selection of other materialsincluding a lamination of layers having varying absorptivecharacteristics. One exemplary material, which may be used as a contactlayer is sold under the trademark XEROFLO® by Kendall Corp., a divisionof Covidien.

Filler 38 may be arranged over contact layer 34 to fill wound “w” to thelevel of the surrounding healthy skin “s” or may over-fill the wound “w”as depicted in FIG. 4A. An absorbent material such as non-woven gauze orreticulated foam may be used for filler 38 to trap or transport anyexudate that migrates through contact layer 34. An antimicrobialdressing sold under the trademark KERLIX® by Kendall Corp., a divisionof Covidien, may be suitable for use as filler 38. To prevent adhesionto the wound “w,” the filler 38 may also comprise a material configuredsuch that any stray fibers do not tend to protrude through apertures ofcontact layer 34 where they may become engulfed by newly forminggranulation tissue. One particular type of material exhibiting thischaracteristic is often referred to as “tow.” The manufacturing processfor synthetic fibers often includes an extrusion of an indeterminatelength of continuous filaments, which are spun together to form fibers.It is the continuous lengths of un-spun filaments which are referred toas tow. A single length of tow formed from a hydrophobic material suchas polyolefin may be laid in the wound bed “w” to form filler 38. Thisarrangement allows for a complete removal of filler 38 when the dressing16 is changed without re-injuring the wound “w.”

Cover layer 40 may be placed over the wound “w” enclosing the contactlayer 34 and filler 38 therein. The periphery of cover layer 40 extendslaterally beyond the perimeter of the wound bed “w” so as to contact thehealthy skin “s” to form a seal over the wound “w.” As depicted in FIG.2, adhesive layer 48 may extend to the periphery of cover layer 40 toprovide the seal with the use of a medical-grade, pressure-sensitiveadhesive. The adhesive layer 48 may be adapted to provide a fluid-tightand bacteria-tight seal around a peripheral region of dressing 16 suchthat exudate cannot escape through the edges of the dressing 16 andexternal air and contaminants may not enter the wound area. To providesuch a barrier, the adhesive layer 48 may, for example, be on the orderof 1.0 to 10 mils thick depending on the adhesive used. In general, ahigh peal-strength adhesive may be used to resist inadvertent lift-off,roll or “flagging,” i.e., a failure of the dressing to adhere to itselfor the patient, at the edges of the cover layer 40. The adhesivedefining the adhesive layer 48 may include, but is not limited to,medical grade acrylics, rubber base or silicone adhesives. Preferably,those adhesives included with the dressing sold under the trademarkPolyskin II Transparent Dressings by Kendall Corp., a division ofCovidien, may be used. Adhesive layer 48 forms a continuous band aroundthe peripheral region of cover layer 40, but contains an opening suchthat the adhesive layer does not extend inwardly to the central areas ofcover layer 40.

As depicted in FIG. 3, reinforcement layer 46 may overlap adhesive layer48 at an outer edge such that an outer periphery of reinforcement layer46 is firmly affixed to backing layer 44. Reinforcement layer 46 extendsto a peripheral region of cover layer 40, but not necessarily to anouter perimeter of the cover layer 40. Reinforcement layer 46,particularly any portion not overlapping the adhesive layer 48, may beaffixed to backing layer 44 with a light coat of an adhesive 57 appliedto the appropriate side of the reinforcement layer 46 or the backinglayer 44. A portion of a wound facing side 52 of the reinforcement layer46 carries no adhesive to prevent adhesion of the cover layer 40 to thefiller 38. An aperture 54 extends through the reinforcement layer 46 topermit fluid communication between the reservoir 14 and vacuum system12.

The reinforcement layer 46 may comprise a mesh of polyethyleneterephtalate (PET) fibers, which offer good liquid resistance making itsuitable for use in a moist wound environment. PET fibers may be used toform woven or non-woven reinforcements having large pore sizes. Some PETreinforcement manufacturing methods provide for interlinking the fiberjunctions to yield a mesh that is flexible in multiple directions andalso does not unravel when cut. One such method is known ashydro-entanglement. PET reinforcements thus manufactured tend to have ahigh shear stiffness that may be useful in reinforcing cover layer 40.One exemplary material, which may be suitable for incorporation intoreinforcement layer 46, is sold under the trademark Sontara® by DuPont.Alternatively, reinforcement layer 46 may be formed from anotherreinforcement or mesh structure having suitable shear stiffness.Examples of suitable structures include extruded netting and aperturedfilms. Suitable materials for use in such alternate structures includePET, polyethylene, nylon and polypropylene. Additionally, wovenstructures may be used for reinforcement layer 46. Acceptable wovenmaterials may include cotton gauze, woven acetate and nylon.

Extending to the periphery of the cover layer 40 is backing layer 44.Backing layer 44 provides a substrate to which reinforcement layer 46and adhesive layer 48 may be affixed. An aperture 56 extends through thebacking layer 44 to permit fluid communication between the reservoir 14and vacuum system 12. Backing layer 44 may be formed from a flexiblepolymeric membrane to serve as a fluid barrier to allow for asub-atmospheric pressure to be established in vacuum reservoir 14, andalso as a microbial barrier preventing contaminants from entering thewound area. For example, backing layer 44 may comprise a polyurethanefilm having a thickness from about 0.8 mils to about 1.0 mil.Preferably, the backing layer 44 is formed from a moisture vaporpermeable membrane to promote the exchange of oxygen and moisture vaporbetween the wound site and the atmosphere. One exemplary material is atransparent membrane sold under the trade name POLYSKIN® II by KendallCorp., a division of Covidien. Other materials which may be suitable foruse in a backing layer include the thin films marketed under the namesTEGADERM™ by 3M of St. Paul, Minn. and OPSITE™ by Smith and Nephew PLCof London, UK. Reinforcement layer 46 may be configured so as not toimpede the transmission of moisture vapor by including, for example, alarge pore size.

As seen in FIG. 4A, reservoir 14 is defined by or within wound dressing16 when applied to the skin. Filler 38 may be included to fill thereservoir 14. Evacuating atmospheric gasses from the reservoir 14 mayimpart a tendency for cover layer 40 to flatten against the wound “w” asdepicted in FIG. 4B. This tendency of cover layer 40 to deform may drawthe peri-wound margins into the wound “w” and put the surrounding skin“s” in tension. This tendency may be counteracted or resisted by theshear stiffness in reinforcement layer 46 such that the cover layer 40may better main its shape. Because reinforcement layer 46 extends to aperipheral region of cover layer 40 and backing layer 44 anchored tohealthy skin “s,” the forces associated with evacuating reservoir 14 maybe transferred beyond the perimeter of the wound “w,” and may bemanifested as compression forces. Thus reinforcement layer 46 reinforcescover layer 40 and vacuum reservoir 14.

A central region of reinforcement layer 46 may be devoid of an adhesivecoating, such that the reinforcement layer 46 may not tend to adhere toor disturb filler 38, particularly as the reduced pressure is removedfrom reservoir 14. Reinforcement layer 46 thus further protects wound“w” to promote healing throughout the evacuation cycles of a VWTprocedure.

Although the foregoing disclosure has been described in some detail byway of illustration and example, for purposes of clarity orunderstanding, it will be obvious that certain changes and modificationsmay be practiced within the scope of the appended claims.

1. A cover layer for a vacuum wound therapy dressing comprising: abacking layer comprising a flexible polymeric membrane; an adhesivelayer adapted to affix the backing layer over a wound bed and provide asubstantially fluid-tight seal around a perimeter of the wound bed; anda reinforcement layer affixed to the backing layer, the reinforcementlayer extending to a peripheral region of the backing layer so as toreinforce a vacuum reservoir over the wound bed.
 2. The cover layeraccording to claim 1, wherein the reinforcement layer comprises a meshformed from polyethylene terephthalate fibers.
 3. The cover layeraccording to claim 1, wherein the adhesive layer is affixed to aperipheral region of the backing layer and includes an opening such thatthe adhesive layer does not extend to a central region of the coverlayer.
 4. The cover layer according to claim 3, wherein the adhesivelayer overlaps a portion of the reinforcement layer such that thereinforcement layer is firmly affixed to the backing layer.
 5. The coverlayer according to claim 1, wherein the backing layer comprises apolyurethane film having a thickness from about 0.8 mils to about 1.0mils.
 6. The cover layer according to claim 1, wherein the backing layerfurther comprises an aperture therein for facilitating connection of avacuum port to the cover.
 7. The cover layer according to claim 6,wherein the vacuum port is affixed to the backing layer, the vacuum porthaving a filter screen therein defining a plurality of openings.
 8. Thecover layer according to claim 1, wherein the backing layer includes amoisture vapor permeable membrane.
 9. A wound dressing system, whichcomprises: a contact layer adapted for positioning adjacent a wound bed;an absorbent filler positioned adjacent the contact layer within thewound bed for collecting liquids exuding from the wound bed; a coverlayer positioned over the wound bed defining a vacuum reservoirtherebetween, the cover layer comprising a backing layer formed from aflexible polymeric membrane, an adhesive layer to provide a seal aroundthe wound bed, and a reinforcement layer affixed to the backing layerand extending to a peripheral region of the cover layer; and a vacuumsystem in fluid communication with the vacuum reservoir.
 10. The wounddressing system according to claim 9, wherein the contact layer isformed from a conical apertured film.
 11. The wound dressing systemaccording to claim 9, wherein the absorbent filler material comprises asingle strand of a polyolefin filament.
 12. The wound dressing systemaccording to claim 9, wherein the vacuum system includes a vacuumsource, a collection canister and a one-way valve.